A two dimensional crystalline layer is found at the surface of the liquid eutectic Au82Si18 alloy above its melting point TM=359∘C. Underlying this crystalline layer we find a layered structure, 6-7 atomic layers thick. This surface layer undergoes a first-order solid-solid phase transition occurring at 371∘C. The crystalline phase observed for T>371 ∘C is stable up to at least 430 ∘C. Grazing Incidence X-ray Diffraction data at T>371 ∘C imply lateral order comprising two coexisting phases of different oblique unit cells, in stark contrast with the single phase with a rectangular unit cell found for low-temperature crystalline phase 359∘C<T<371∘C.
@article{arxiv.cond-mat/0702413,
title = {Crystalline Surface Phases of the Liquid Au-Si Eutectic Alloy},
author = {Oleg G. Shpyrko and Reinhard Streitel and Venkatachalapathy S. K. Balagurusamy and Alexei Yu. Grigoriev and Moshe Deutsch and Benjamin M. Ocko and Mati Meron and Binhua Lin and Peter S. Pershan},
journal= {arXiv preprint arXiv:cond-mat/0702413},
year = {2009}
}